高能强流重离子加速器动态真空效应研究

Intermediate charge state heavy ion beam will be adopted as the reference ion in the high energy high intensity heavy ion accelerator to overcome the space charge limit and fulfill the high intensity requirements of physics experiments. However, beam losses are easily caused by the interaction between the intermediate charge state ions and the residual gas. The beam losses would cause the ion-stimulated desorption, decay of beam lifetime and even the shutdown of the accelerator. As a result, the studies on the dynamic vacuum simulation, vacuum material desorption measurement and stable dynamic vacuum method must be carried out. Based on the previous research results of beam loss mechanism, this research project will study the method of dynamic vacuum simulation and measurement. New experiment platform will be established in the HIRFL-CSR to measure the different vacuum material desorption in room and cryogenic temperature. Investigating on the change of cryogenic material desorption with beam energy. The method of stabling dynamic vacuum system will be proposed. A simulation program which integrates beam loss calculation, dynamic vacuum simulation and lattice optimization will be designed. Those research results will provide important theory basis and design reference for the high intensity and high energy heavy ion accelerator facility in the future.

高能强流重离子加速器将采用中间电荷态的离子以突破空间电荷限，进而满足各项物理实验对高流强的需求，然而该电荷态的离子与残余气体作用后容易诱发束流损失致使腔体吸附的粒子解吸，引起系统真空度动态变化，造成束流寿命减小，甚至导致加速器停止运行。因此，在束流损失计算完成的基础上，动态真空的模拟计算、真空材料解吸率测量及稳定真空系统的方法研究将是高能强流重离子加速器中亟待开展的工作。本项目将基于束流损失机制的前期研究成果，开展动态真空模拟计算和测量方法研究；搭建基于HIRFL-CSR 的测试平台，测量常温、低温真空腔不同镀膜材料的解吸率，揭示常温、低温真空材料解吸率随束流能量的变化规律；探索维持强流重离子加速器中动态真空系统稳定的新方法；实现集束流损失计算、动态真空模拟和Lattice优化于一体的模拟软件设计，本项目的研究结果将为今后建设的高能强流重离子加速器提供重要的理论依据和设计参考。

本项目基于前期基金项目的束流损失机制的研究成果，开展了动态真空模拟计算和测量方法研究；搭建了基于HIRFL-CSR装置PISA终端和SSC-Linac直线加速器的实验测试平台，测量了常温、低温真空腔不同镀膜材料的解吸率，揭示了常温真空材料解吸率随束流能量的变化规律，解吸率与材料的电子能损的平方成正比关系，提高了系数的精度；首次发现了陶瓷材料在束流清洗效应下的表征现象；实现了集束流损失计算、动态真空模拟和Lattice优化于一体的模拟软件设计，并成功应用于强流重离子加速器装置HIAF项目的前期设计工作中，为今后建设的高能强流重离子加速器提供了重要的理论依据和设计参考经验。